In machinery which processes fluid between high and low pressures there is a need to provide a seal between the high and low pressure regions in order to maintain efficient fluid processing operation. An example of such machinery is turbomachinery such as a turboexpander or a turbocompressor. Often the most appropriate place to position such a seal is between mating parts of such machinery since such mating parts will not form an effective seal just by themselves due to differential thermal movement of the parts, movement due to pressure differences, and fluid leakage because of the large pressure differences which are often involved. The machinery art has developed numerous seals for this application. Generally such seals are characterized by being on one of the mating parts and forms an effective seal when the other of the mating parts is properly positioned in the machinery.
A problem with this arrangement arises when the mating parts are such that their positioning is not easily observable with respect to the seal. That is, the positioning of the mating parts obscures vision of the seal as the parts are brought together. This creates the likelihood that the seal could be damaged during the assembly of the machinery and thus not function properly when the machinery is put into operation. The problem of seal damage during such a blind fit-up is even more acute when the sealing must be done in two directions e.g. both radially and axially.
Another problem arises if the parts themselves are misaligned initially or become misaligned during operation. Since the seal is on one of the parts, the misalignment compromises the effectiveness of the seal even if the seal itself is not damaged.
Accordingly it is an object of this invention to provide an improved seal assembly for sealing high and low pressure regions between mating parts of machinery.
It is another object of this invention to provide an improved seal assembly which reduces the likelihood of seal damage which might be caused when mating parts require a blind fit-up.
It is yet another object of this invention to provide an improved seal assembly which effectively seals high and low pressure regions between mating parts of machinery in two different directions.
It is a further object of this invention to provide an improved seal assembly which will enable effective seal operation even if mating parts are or become misaligned.